Abstract : This paper presents a practical study of a new silicon physical unclonable function (PUF). It is based on recently proposed transient effect ring oscillator (TERO) cells that were originally designed for a true random number generator (TRNG). The proposed PUF has state of the art PUF characteristics with a good ratio of PUF response stability to length. The novel architecture using differential structures guarantees high stability of the TERO-PUF response and low sensitivity to temperature. The area of the TERO-PUF is relatively high, but is still comparable with other PUF designs. However, since the same piece of hardware can be used for both PUF and random number generation, the proposed principle offers an interesting area efficient mixed solution.